Chair back



FIG. 1 is a front perspective view of a chair back, in accordance with the present invention;

FIG. 2 is a front elevation view of the chair back as shown in FIG. 1;

FIG. 3 is a back elevation view of the chair back as shown in FIG. 1;

FIG. 4 is a left side elevation view of the chair back as shown in FIG. 1;

FIG. 5 is a right side elevation view of the chair back as shown in FIG. 1; and,

FIG. 6 is a top plan view of the chair back as shown in FIG. 1.

The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a chair back, as shown and described. 